The guys with machetes?
Were they a different gang come in to take advantage of the mayhem, or were they working for the main baddie? I thought they were a different gang when they started off killing the injured baddies and they had a kind of gang signature with the machetes. But then they were only looking for the police. I got a little confused.
Also, why would you start stabbing an apparently ordinary looking wall rather then looking for a doorway if you thought someone was in there?